The economic, architectural, regulatory, and technological trends during the evolution of the public switched networks to and beyond the year 2000 will create a more fragmented (less unified) network of networks, and the National Communications System and other users of the public switched networks will have to factor this fragmentation into their planning for national security emergency preparedness.
Virtually every segment of the nation depends on reliable communications, and no business or institution could perform its normal functions without the smooth operation of its voice and data communications networks. The committee, after careful study, has concluded that a serious threat to communications infrastructure is developing. Public communications networks are becoming increasingly vulnerable to widespread damage from natural, accidental, capricious, or hostile agents.
The government of the United States must be able to control and direct the allocation and use of its critical national resources in the event of national emergency conditions. This ability to control and direct depends on reliable, survivable communications. The rich fabric of transmission facilities, switches, and embedded technology that makes up the nation’s public switched network, now a network
of networks, is the communications resource upon which all levels of government and industry will depend to control and direct resources and assets. This network of networks is viewed as the U.S. nationwide telecommunications network, made up of many common carrier, private, institutional, research, and other networks.
For the federal government, the Manager of the National Communications System (NCS) has the responsibility to plan the architecture for a survivable communications capability to support the nation’s reconstitution in the event of a national emergency (Executive Office of the President, 1984). The responsibility for similar planning in the industrial sector does not exist. For the government’s part, considerable effort has been devoted to this undertaking. Three interrelated programs are being implemented that address organization, planning, and implementation of national security emergency preparedness (NSEP) telecommunications.
The programs are the Commercial Satellite Interconnectivity program, the Commercial Network Survivability program, and the Nationwide Emergency Telecommunications Service. These programs are cited in Chapter 2 and are described and analyzed fully in the committee’s interim report, which documented the first phase of the committee’s overall task to assist the NCS Manager (National Research Council, 1987). The committee wishes, at the outset, to commend the NCS for its diligence in carrying out its mission. NCS is addressing the problems posed by network vulnerabilities to the best of its ability, consistent with its current resources and powers. The committee also commends the National Security Telecommunications Advisory Committee (NSTAC) for bringing together industry and government representatives to address NSEP issues.
However, the telecommunications industry as a whole has not sufficiently addressed survivability or other aspects of assuring system availability (Center for Strategic and International Studies, 1984; Telecommunications Reports, 1988).
THE COMMITTEE’S APPROACH
The second phase of the committee’s work was to assess the vulnerabilities of the public switched networks to a variety of threats and to review the switching, synchronization, and network control aspects of
surviving network elements. Issues of restoration and reconstitution of communications were also addressed. Two full committee meetings and numerous briefings were devoted solely to assessing whether adequate synchronization capabilities are likely to exist to support NSEP telecommunications restoration and reconstitution after a natural disaster or attack on the country. The committee concluded that the current standards of synchronization do ensure an adequate margin of safety. The committee then turned its attention to the subject of the survivability of network switching and control. It was to take into account redundancy, alternative connectivity, and emerging technologies and then assess the adequacy of switching facilities to permit restoration and reconstitution. Given the proliferation of emerging technologies and a rapidly evolving nationwide network, it was considered desirable to explore a somewhat broader NSEP perspective including circuit, burst, and packet switching as well as the control aspects. Network evolution is of significant importance, particularly since new vulnerabilities are introduced by an open network architecture, new embedded technologies, widely distributed software, and the trend toward customer control of software.
The Deputy Manager of NCS agreed that the committee should examine switching and control in the context of a broader review focused on what the public switched networks might look like in the year 2000 and what the NCS planners may be faced with in fulfilling the President’s National Security Decision Directive (NSDD-97). The committee heard presentations from industry network planners, systems architects, technologists, and engineers as well as regulators, manufacturers, academics, network management experts, and individuals from the research and development community. The committee’s principal conclusions appear in italics below, preceded by brief introductory discussions.
Since public and private organizations depend critically on networks, significant network failures will cause great economic damage to users and providers and also may disrupt the ability of government to provide basic services, such as health care, law enforcement, and fire protection, as well as national defense.
The committee believes that the consequences of network failure are becoming much greater for both customers and network providers than they were a decade ago.
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The growing dependence of the United States on its networks is occurring at a time when they are becoming more vulnerable to widescale disruption. This unfortunate situation is emerging because of converging trends in technology, economics, and regulatory practice.
It is becoming increasingly easier to make the public switched networks inoperable.
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Among the technology trends that are increasing vulnerability are the development and perfection of fiber optic technology and the advances in digital switching. Optical fibers are able to offer great increases in traffic-carrying capacity when compared to earlier transmission schemes. Consequently, new transmission routes are primarily fiber. While a fiber route is not inherently more vulnerable than alternative methods of landline transmission, fewer fiber routes are needed to meet national capacity requirements.
The power of optical fiber technology is diminishing the number of geographic transmission routes, increasing the concentration of traffic within those routes, reducing the use of other transmission technologies, and restricting spatial diversity. All these changes are resulting in an increase in network vulnerability.
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Switching technology has advanced in parallel with transmission technology. Today’s digital switches are physically smaller but have substantially greater capacity than earlier electronic switches. They also have the ability to control remote unmanned systems. Therefore, a single switching node may support communications for many tens of thousands of subscribers in multiple communities. Furthermore, each major transmission provider is embarked on an evolutionary path toward reducing costs through centralizing control of its network in fewer switching centers and a small number of signal transfer points.
The evolution of switching technology is resulting in fewer switches, a concentration of control, and thus greater vulnerability of the public switched networks.
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At the same time that switches have become more powerful and
physically smaller, the cost of investment capital, labor, and real estate has continued upward and has helped motivate communications providers to consolidate operations into fewer geographic facilities. As a result this trend increases the potential for catastrophic disruption that may be caused by damage to even a single location.
There is a progressive concentration of various traffic in and through single buildings resulting in increasing vulnerability. It is common for the following types of equipment to be in one building: signal transfer points; class 3, 4, and 5 switches; packet switches; mobile telephone switching offices; and private line terminations.
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During the period of the committee’s study, a fire (May 1988) at an Illinois Bell Telephone Company central office in Hinsdale disrupted communications services for tens of thousands of households and businesses (National Communications System, 1988). The fire affected telephone service and data communications in the public switched network as well as in many private communications networks with facilities routed through the Hinsdale office. Initially thousands of user services were disrupted. Although essential government facilities for air traffic control were rapidly restored, many businesses and most residences did not regain service for up to several weeks. The economic consequences of the failure were widely reported. The Hinsdale situation has three separate components that may need to be differentiated. The first is the accidental fire; little can be done to eliminate such accidents. The second component of concern is the extent of damage caused by the evolution of communications to higher and higher levels of concentration. The third is the economic disruption that can occur as society increasingly relies on the public switched networks.
The committee points to the Hinsdale event as an early warning for the need to broaden the scope of national security emergency preparedness in an information society.
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Along with developments in transmission and switching, which concentrate network capacity, the public switched networks are centralizing network database intelligence through improvements in software technology. Software is creating new services for which users need
access to previously masked aspects of network control, management, and operations. At the same time, computer “hackers” have become more sophisticated in using telecommunications networks to penetrate remote computer software.
The public switched networks are increasingly controlled by and dependent on software that will offer open public access to executable code and databases for user configuration of features, a situation that creates vulnerability to damage by “hackers,” “viruses,” “worms,” and “time bombs.”
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The competitive environment of the past decade has caused a proliferation of networks and network vendors. One would think this proliferation should decrease vulnerability because of the added redundancy provided by multiple networks. However, in practice, there is actually less than meets the eye. Some of these networks traverse the same geographic rights-of-way and are thus vulnerable to the same physical attacks. Further, competitive factors and the large array of technical alternatives have increased incompatibilities in public and private networks, so that it will be difficult to use the surviving assets in one network to back up those of another.
STRUCTURE OF THE REPORT
These vulnerabilities, with appropriate recommendations, were summarized in the Executive Summary. Chapter 2 traces the evolution of NSEP policy from 1979 to the present. It also summarizes the NCS programs and initiatives that address the organizational, planning, and implementing structures for NSEP telecommunications. Chapter 3 presents an overview of the probable evolution of the public switched networks through the year 2000. It discusses the probable effects of the regulatory environment, technology advances, competition, and customer demand. Chapter 4 focuses on the regulatory drivers of the public switched network evolution. Six major areas are investigated. They are (1) expected changes in jurisdictional responsibilities, (2) the trends toward Open Network Architecture, (3) the impact of broadband services regulation, (4) the gradual adoption of market-based pricing for services other than basic voice telephone service, (5) the effects of bypass, and (6) the trend toward deregulation of local exchange carriers. Chapter 5 discusses a number
of technological driving forces, notably fiber optics, digital switching, and customer controlled software, seen to be major influences in the evolving network, and relates their effects to network architecture, services, and vulnerabilities. In Chapter 6 the committee analyzes the impact of competition on the public switched network and relates this subject to NSEP issues. It includes a discussion of the providers of local and interexchange services, cellular mobile radio, customer-premises equipment, value-added networks, electronic databases, cable television, and some innovative services. Chapter 7 looks at a number of user needs that derive from what new technology may offer and would be affordable to a wide customer base. The committee discusses integrated voice, data, and image applications that will likely be available to residential, commercial, and institutional subscribers by the year 2000. It also points out how customer demand for more and better services can amplify network vulnerabilities that may result.
Center for Strategic and International Studies. 1984. America’s Hidden Vulnerabilities: Crisis Management in a Society of Networks. R.H. Wilcox and P.J. Garrity, eds. Washington, D.C.: Georgetown University.
Executive Office of the President. 1984. Assignment of National Security and Emergency Preparedness Telecommunications Functions. Executive Order 12472. Washington, D.C.: U.S. Government Printing Office. April 3.
National Communications System. 1988. May 8, 1988 Hinsdale, Illinois Telecommunications Outage. Washington, D.C.: National Communications System.
National Research Council. 1987. Nationwide Emergency Telecommunications Service for National Security Telecommunications. Washington, D.C.: National Academy Press.
Telecommunications Reports. 1988. Ameritech’s Weiss says telecommunications policy should be a national priority. November 21.